You can save the output of most Linux commands to files using output redirection. All you need to do it is add a greater than symbol at the end of the command and a file name to save to.

Caution: this will overwrite the file you are sending the output to.

Appending output

In order to have the saved output appended to the end of the file without overwriting it, simply put two greater than signs.

Saving errors to files

The previous examples with only save the normal output to files. Any errors are typically sent to something call standard error. You can save these errors to files just like saving the output using a slightly different syntax. All you need to change is to add a 2 before the greater than sign(s).

When running the previous example as a normal user, you should get several errors about permissions. The first example will save all the errors to the file myerror.log and overwrite anything previously in the file. The second example will do the same thing except it will append the errors to the file without overwriting it.

Saving output and errors

You can save the output of a command to a file and the errors of the same command to a different file

It is possible to save both the output and errors to the same file using the following example.

The number 2 is the file descriptor for standard error and the number 1 is the file descriptor for standard output. Putting 2>&1 at the end of the command (after having redirected the output) is simply saying send standard error to the same place as standard output.